关键词: 棉秆炭; 连作棉花; 根际真菌群落多样性; 土壤理化性质; 黄萎病

Abstract: 【Objective】 The method of cotton stover incorporation directly affects the physicochemical properties, soil microbial characteristics and occurrence of soil-borne diseases under cotton cultivation, so this project aims to study relationships between continuous cropping cotton rhizosphere soil fungi community diversity and soil physicochemical properties and Verticillium wilt disease in the hope of providing scientific basis and theoretical guidance for rational utilization of cotton stover biochar and the prevention and control of continuous cropping barrier of cotton.【Method】In this study, field trials were conducted to examine the effects of cotton stover biochar on the physicochemical properties, fungal communities, and occurrence of Verticillium wilt disease over 2 years in soil under continuous cotton cropping in Xinjiang, China. The experiment was a factorial design with the four treatments: 1) normal fertilizer with cotton stover removed (NPK); 2) normal fertilizers with powdered cotton stover returned to fields (NPKS); 3) normal fertilizer plus cotton stover biochar applied at 22.50 t/hm² (NPKB1); and 4) normal fertilizer plus cotton stover biochar applied at 45.00 t/hm² (NPKB2).【Result】Compared with NPK and NPKS treatments, fungi diversity was significantly correlated with physicochemical properties in the NPKB1 and NPKB2 treatments. The 454 high-throughput fungal DNA sequencing data showed that the NPKB2 treatment significantly reduced soil fungal diversity in the soil under continuous cotton cropping. As compared to NPK treatments, OTU abundance of fungal decreased by 15.63% and 46.25%(P<0.05)in NPKS and NPKB2 treatments, the Shannon index decreased by 11.81% and 65.40%. Different dosage of cotton stover biochar had a great influence on the number of Ascomycota and Zygomycota, but the number of mycorrhizal fungi was decreased. Analysis of microbial populations at the genus level revealed that the pathogenic fungi, including Gibberella, Fusarium and Verticillium wilt significantly decreased under the NPKB2 treatment. Compared with NPK and NPKS treatments, the NPKB1 and NPKB2 treatments significantly increased soil organic matter (OM), available K and N, whereas available P decreased in the soil. Cotton stover biochar had no significant effect on soil pH, but significantly increased soil electrical conductivity. In RDA analysis, OM and AN were important environmental factors affecting the community structure of soil fungi in cotton rhizosphere. In RDA analysis, OM and AN were important environmental factors affecting the community structure of soil fungi in cotton rhizosphere. Compared with NPK and NPKS treatments, the NPKB1 treatment increased the incidence and disease index of Verticillium wilt. For NPKB2 treatment, no significant decrease was found in the incidence of Verticillium wilt; however, the disease index declined by 2.2% and 15.0%, respectively.【Conclusion】This study showed that cotton stover biochar reduced fungal diversity and the number of Verticillium wilt in rhizosphere soil of continuous cropping cotton, and increased soil nutrient content. Although the incorporation of cotton stover biochar did not significantly lower the incidence of cotton Verticillium wilt but tended to relieve the disease severity.

Key words: cotton stover biochar; continuous cropping cotton; rhizosphere fungal community diversity; soil physicochemical properties, Verticillium wilt disease ;  ;